Low Cost Assistive Technology Button

Currently there are several 3.5mm jack buttons on the market for assistive technology use or projects. These are large buttons (50mm diameter plus) that require a low force to press and often give a satifying click or pop. In the UK at least these are rather expensive so I decided to build a lower cost design using off the shelf parts, requiring basic soldering skills.

I've assumed that anyone checking this project out may want to get more actively involved so I'll basic options for tools and supplies plus a more advanced option. See how you feel.

Good soldering iron starter kit - available here

or a more advanced soldering station with holder that I'm using here

Lead free solder (smaller packs are available) here

3.5mm mono jack cable (1.2m long) - here

Or 3.5mm stereo jack cable (1.5m long used in this project which can be lower cost and requires the two non tip wires to be soldered together - mono jack cable can also be used) here

Plastic electric enclosure (116x 116 x 62mm) with rounded edges and plastic screws - here

Large arcade button (100mm dia - blue selected here but multiple colours available) - here

Drill - here

25mm diameter hole drill bit - here

5mm diameter drill bit - here

Wire strippers (I use these as they take the work out of wire sizing) - here

Wire cutters - here

Flat bladed screw driver - hardware shop of choice

Pencil - makers choice

Ruler or straight edge

These links are only suggestions for these supplies mind. I have included a few affiliate links for some supplies but only because they are cheap and effective supplies.

I underscrewed the lid and used a pencil and a ruler to mark the centre of the top of the box going across the corners as shown.

Then using the drill with the 25mm holesaw bit, drill the hole.

I then soaked it in water overnight to get the label off cleanly.

Change the drill bit to the 5mm bit and pick a side for the 5mm hole. This is where the 3.5mm jack lead is going to protrude from.

Use the wire cutters to remove one of the 3.5mm jacks from the jack cable.

Push the cut end of the 3.5mm jack cable through the hole in the enclosure from the outside. I gently tie a knot on the inside, at about 200mm from the trailing end to prevent any cable pulls from damaging the solder joint to the switch that we will now add.

Assemble the button to the top of the lid with the nut on the underside before clipping the switch in place.

For this project I've used a 3.5mm stereo cable which means the white and yellow leads need to be soldered to the same tab on the switch. This gives the white and yellow wires going to one tab and the red wire going to the Common tab.

Depending on how you want the switch to work you can use the Normally Open contact, as I have here, which will make the switch join when pressed. The button also has a Normally Closed contact which breaks the join when the switch is pressed.

You decide how you would like this switch to operate when you build it.

Option - the button I have chosen also has a light that can be wired up too however I have left this off for simplicity.

Place the lid onto the enclosure, and screw down the screws.

Now test and enjoy :-)